Introduction

As of today the Sigma AF 80-400mm f/4.5-5.6 EX APO OS is the only lens in the Sigma
lineup featuring an OS (Optical Stabilizer) similar to Canon's IS and Nikon's VR.
The lens is a direct competitor to the Canon EF 100-400mm f/4.5-5.6 USM L IS and
the Nikon AF 80-400mm f/4.5-5.6 ED VR and Sigma is even brave enough to approach
the price point of those two lenses quite closely. Surprisingly (or sadly) the lens
is only available in Canon and Nikon mount - a quite odd marketing decision regarding
the lack of image stabilization on the Pentax and Olympus side of life. The tested
lens is the older variant without Sigma's new DG (Digital) coating but regarding
the unaltered design most findings should be valid for the current lens as well.
It's a full frame lens perfectly usable on both film as well as digital SLRs but
as usual we'll have a look how it performs on a popular APS-C DSLR where
its field-of-view is equivalent to 128-640mm.

The similarities between the Sigma, the Canon and the Nikon are quite striking so let's
have a look at the paperwork first:

Sigma AF 80-400mm f/4.5-5.6 EX APO OS

Canon EF 100-400mm f/4.5-5.6 USM L IS

Nikkor AF 80-400mm f/4.5-5.6 ED VR

Elements/Groups

20/14

17/14

17/13

Special Elements

3 SLD

1 CaF2 + 1 SUD

3 ED

Image Stabilizer Efficiency (*)

3 f-stops

2 f-stops

3 f-stops

Aperture blades

9

8

9

Min. focus (magnification)

1.8m (1:5)

1.8m (1:5)

2.3m (1:4.8?)

Floating Elements

no

yes

no

AF motor

conventional micro motor

ultrasonic

conventional micro motor

Zoom tpye

Linear extension Type (zoom ring)

Linear extension Type (push/pull)

Linear extension Type (zoom ring)

Size

192x95mm

189x92mm

171x91mm

Weight

1750g

1380g

1340g

Filter size

77mm

77mm

77mm

approx. Price (EUR)

1050€

1450€

1500€

(*) according to manufacturer

The OS (Optical Stabilizer) works basically identical to Canon or Nikon variants.
The camera motion is detected by gyro sensors which measure the angle and speed of the shake.
This information is used to shift a lens group off the optical axis (basically a forced decentering)
to counteract this motion. The result is a significant improvement of handholdability under critical
conditions. The Sigma also features two OS modes - one for static scenes that corrects motion
both horizontally as well as vertically and a 2nd mode for panning (object tracking) that corrects
vertical motion only.
Sigma claims an efficiency of three f-stops but in the field it didn't really feel superior
to Canon's IS. Subjectively it even felt like I had more outliers out there. Better
expect 1/200sec @ 400mm (640mm equiv.) as the minimum in shutter speed. A rather annoying
aspect of the OS is an increased shutter delay when shooting subsequent images (image bursts).
The issue seems to originate in the high power drain of the OS and it seems to happen
on all EOS cameras (even with attached battery pack). So far this is the first IS/OS lens tested
to date showing such an odd behavior.

The build quality of this lens is very impressive. The zoom action is a little on the stiff side
but the zoom ring provides a better control of the zoom action compared to Canon's
push-pull design. As you can see in the product shots above the lens extends significantly
when zooming towards the long end but the inner barrel remains very stable. The included
deep lens hood adds quite a bit of length on top. It is worth to
notice that the lens sucks in quite a bit of air so there may be question marks regarding
the accumulation of dust over time. This is true for the two genuine lenses as well
though - neither features a sealing. The detachable tripod mount with its ergonomic
grip feels excellent and very convenient when carrying the lens.
The focus ring operates exceptionally smooth and very well damped.

Unfortunately the conventional AF motor is rather noisy and slow - certainly not comparable to the
Canon EF 100-400L USM IS (nor is the Nikkor). Surprisingly manual focusing remains possible
in AF mode which is highly unusual regarding the AF drive type. Thanks to a rear-focusing
group the front element does not rotate so using a polarizer remains easily possible (at least
without attached hood). Sigma has also implemented a transport lock which keeps the lens at
its 80mm setting.
The AF 80-400mm f/4.5-5.6 EX OS is compatible to both Sigma AF EX
converters but only at cost of AF operation. However, regarding the rather slow max.
aperture this cannot be more than an emergency solution.